Iranian Journal of Materials Science & EngineeringIranian Journal of Materials Science & EngineeringIJMSEEngineering & Technologyhttp://ijmse.iust.ac.ir18agent21735-08082383-388210.22068/ijmseenjalali138861gregorian20099163online1fulltextenMECHANISMS OFPRECIPITATES FORMATION IN AN Al- Cu- Li-ZrALLOYUSINGDSC TECHNIQUE AND ELECTRICALRESISTANCE MEASUREMENTSگروه سرامیکCeramicsResearch paperResearch paperAbstract: Guinier-Preston (GP) zone formation and precipitation behavior of T1 (Al2CuLi) phase during the ageingof an Al-Cu-Li-Zr alloy was studied by differential scanning calorimetry (DSC) technique and electrical resistancemeasurement of the samples. Results show that endothermic effects in the thermograms of the alloy between 180°Cand 240°C can be related to the enthalpy of GPzones dissolution. Formation of GPzones in the structure increasedhardness, tensile strength and electrical resistance of the Al-Cu-Li-Zr alloy. Furthermore, precipitation of T1 phaseoccurred in temperature range of 250ºC to 300ºC whereas its dissolution occurred within the temperature of 450-530ºC. Activation energies for precipitation and dissolution of T1 phase which were determined for the first time inthis research, were 122.1(kJ/mol) and 130.3(kJ/mol) respectively. Results of electrical resistance measurementsshowed that an increase in the aging time resulted in the reduction of electrical resistance of the aged samples.Keywords: aluminum- lithium alloys, DSC; activation energy, natural aging, Al-Cu-Li-Zr alloy, T1 phase, dissolutionenergies1520http://ijmse.iust.ac.ir/browse.php?a_code=A-10-3-98&slc_lang=en&sid=1A. Shokuhfar180031947532846003180031947532846003NoS. Ahmadish.ahmadi@modares.ac.ir1800319475328460082118003194753284600821Yes
H. Arabi1800319475328460085018003194753284600850NoS. Nouri1800319475328460085118003194753284600851No